This invention pertains to fused material comprised of Al2O3-rare earth oxide-ZrO2 eutectics. Examples of useful articles comprising fused Al2O3-rare earth oxide eutectic material include fibers and abrasive particles.
A variety of fused eutectic metal oxide materials are known in the art, including binary and ternary eutectic materials. Fused eutectic metal oxide materials are typically made by charging a furnace with sources of the various metal oxides, as well as other desired additives, heating the material above its melting point, and cooling the melt to provide a solidified mass (see, e.g., U.S. Pat. No. 1,161,620 (Coulter), U.S. Pat. No. 1,192,709 (Tone), U.S. Pat. No. 1,247,337 (Saunders et al.), U.S. Pat. No. 1,268,533 (Allen), U.S. Pat. No. 2,424,645 (Baumann et al.) U.S. Pat. No. 3,891,408 (Rowse et al.), U.S. Pat. No. 3,781,172 (Pett et al.), U.S. Pat. No. 3,893,826 (Quinan et al.), U.S. Pat. No. 4,126,429 (Watson), U.S. Pat. No. 4,457,767 (Poon et al.), U.S. Pat. No. 5,143,522 (Gibson et al.),. U.S. Pat. No. 5,023,212 (Dubots et. al), and U.S. Pat. No. 5,336,280 (Dubots et. al).
There is, however, a continuing desire for new materials which may offer performance characteristics (including combinations of characteristics) that are different than conventional materials, are easier to make, and/or cheaper to make.
The present invention provides a fused, crystalline eutectic material comprising eutectic of at least (a) crystalline ZrO2 and (b) at least two of (i) crystalline Al2O3, (ii) first crystalline complex Al2O3.rare earth oxide, or (iii) second, different (i.e., different from the first crystalline complex Al2O3.rare earth oxide), crystalline complex Al2O3.rare earth oxide material.
One preferred eutectic material according to the present invention comprises eutectic of at least (a) crystalline ZrO2 (b) crystalline Al2O3, and crystalline complex Al203.rare earth oxide. Another preferred eutectic material according to the present invention comprises eutectic of at least (a) crystalline ZrO2, (b) first crystalline complex Al2O3.rare earth oxide, and (c) second, different, crystalline complex Al2O3.rare earth oxide.
In another aspect, the present invention provides a fused, crystalline eutectic material comprising eutectic of at least (a) crystalline complex Al2O3.rare earth oxide and (b) crystalline ZrO2.
In another aspect, a fused, crystalline material according to the present invention preferably comprises, on a theoretical oxide basis, at least 30 percent (or even at least 40, 50, 60, 70, or 80 percent) by weight Al2O3, based on the total metal oxide content the material.
In this application:
xe2x80x9csimple metal oxidexe2x80x9d refers to a metal oxide comprised of a one or more of the same metal element and oxygen (e.g., Al2O3, CeO2, MgO, SiO2, and Y2O3);
xe2x80x9ccomplex metal oxidexe2x80x9d refers to a metal oxide comprised of two or more different metal elements and oxygen (e.g., CeAl11O18, Dy3Al5O12, MgAl2O4, and Y3Al5O12);
xe2x80x9ccomplex Al2O3.metal oxidexe2x80x9d refers to a complex metal oxide comprised of, on a theoretical oxide basis, Al2O3 and one or more metal elements other than Al (e.g., CeAl11O18, Dy3Al5O12, MgAl2O4, and Y3Al5O12);
xe2x80x9ccomplex Al2O3.Y2O3xe2x80x9d refers to a complex metal oxide comprised of, on a theoretical oxide basis, Al2O3 and Y3O3 (e.g., Y3Al5O12);
xe2x80x9ccomplex Al2O3.rare earth oxidexe2x80x9d or xe2x80x9ccomplex Al2O3.REOxe2x80x9d refers to a complex metal oxide comprised of, on a theoretical oxide basis, Al2O3 and rare earth oxide (e.g., CeAl11O18 and Dy3Al5O12);
xe2x80x9crare earth oxidesxe2x80x9d refer to, on a theoretical oxide basis, CeO2, Dy2O3, Er2O3, Eu2O3, Gd2O3, Ho2O3, La2O3, Lu2O3, Nd2O3, Pr6O11, Sm2O3, Th4O7, Tm2O3, and Yb2O3; and
xe2x80x9cREOxe2x80x9d means rare earth oxide.
In another aspect, the present invention provides a method for making fused, crystalline material according to the present invention, the method comprising:
melting at least one Al2O3 source, at least one rare earth oxide source, and at least one ZrO2 source to provide a melt; and
converting the melt to the fused, crystalline material.
Fused crystalline material according to the present invention can be made, formed as, or converted into fibers or abrasive particles.